Gaseous developing apparatus



May 30, 1944.

H. H. STEGLICH 2,350,257

GASEOUS DEVELOPINSE APPARATUS Filed Nov. 13, 1940 HERBERT H. STEGL I CH INVENTOR ATTORNEYS Patentcd May 30, 1944 GASEOUS DEVELOPING APPARATUS Herbert H. Steglich, Binghamton; N. 1., assignor to General Aniline & Film Comration, New York, N. Y., a corporation of Delaware Application November 13, 1940, Serial No. 365,559

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The present invention is concerned with an apparatus for the development of exposed lightsensitive or radiation-sensitive material by means of a gaseous developer. More particularly, the invention covers an apparatus of this type which is capable of operation at extremely slow speeds.

Many devices are known for the gaseous development of exposed light-sensitive materials. In most of these constructions a suitable developing chamber is provided with a perforated plate which forms one wall of said chamber. The exposed material is moved across said perforated plate and is held in contact therewith by any desired conveying means, such as an endless gas-tight belt carried by rollers. Within the chamber it is customary to provide an evaporating trough or gutter in which there is a heating unit. The liquid to be vaporized is passed into said evaporating trough at a controlled rate and is then heated and vaporized so that the resulting gas may act on the exposed printing material which is passed over the perforated plate.

In many of these prior art devices, additional heating units have been arranged within or near the developing chamber. These additional heaters are designed to prevent condensation near the printing material. It has been impossible, however, to develop the light-sensitive material in such an apparatus at speeds considerably slower than, for example, 22 inches per minute, without serious wrinkling of said material. The speed mentioned above is the rate at which the printing material is moved across said perforated plate.

With the disadvantages of the prior art constructions in view, it is accordingly one object of this invention to provide a new and useful gaseous developing apparatus.

It is another object to provide such a device which is capable of slow speed operation without wrinkling or deformation of the material which is to be developed.

Other objects and advantages of this invention will be readily apparent from the following specification.

I have found that the foregoing objects are accomplished by the provision of an auxiliary heating unit at the rear edge of the perforated plate. This heating unit is preferably insulated from the rest of the developing chamber and does not affect the temperature of the developing gas to any great extent. The presence of this auxiliary heating unit, however, serves to prevent wrinkling of the printing material when plates (not shown).

said material is moved across the plate at extremely slow speeds. With the aid of this construction, it is possible to move the material at speeds considerably slower than 22 inches per minute, and in mamr cases as slowly as 4 inches per minute, without deformation or wrinkling.

In the attached drawing forming a part of this application, the single figure is a perspective view of a gaseous developing apparatus which incorporates the present invention. The end plate and housing have been removed, and the conveying band has been partly broken away for the sake of clarity.

In order that those persons skilled in the art may fully understand the nature and scope of this invention, I shall now give a detailed description of the same with particular reference to the above mentioned drawing, in which like reference characters indicate like parts.

The apparatus includes a developing chamber or tank III, which may be formed from aluminum, stainless steel, or any suitable material. The material is bent to its final shape, and its edges are joined in a gas-tight manner as at H. The ends of the chamber are closed by suitable end One wall of this developing chamber is provided with a series of openings or perforations I! which readily permit the passage of the developing gases through said wall. This perforated wall or plate is preferably at the top of the developing chamber. The material to be developed is held against said plate and is moved across the plate by means of the endless conveying band I3, which may be made of rubber or other gas-tight material. Band I! is mounted on rollers II and ii at the front and rear edges of said perforated plate. Roller II is driven at the desired speed by any customary mechanical means. Roller II, on the other hand, is preferably not driven. Because of this arrangement of the rollers, it will be clear that the endless band will be drawn tightly across the developing chamber from the roller ll to the roller ll.

The material to be developed is inserted at It and is carried across the top of the chamber (1. e. across the perforated plate) and emerges at 23. Because of the perforations I! the gaseous developer will have. ready access to the printing material and will accomplish the developing operation in known manner. At the same time, the close contact of the endless band against said perforated plate prevents the escape of any substantial amount of the developing gas.

as The developinl gas is produced in known man- According to the present invention, an aux-' iliary heating unit I9 is positioned at the rear edge of the perforated plate or, in other words, at that edge of the plate over which the printing material passes as the development operation is completed. This auxiliary heating unit is is preferably insulated from the rest of the developing chamber, so that it will not upset the carefully controlled temperature conditions necessary for the development operation itself. As shown in the drawing; the heating unit I9 is within the chamber and is insulated from the rest of the chamber by the partition 20 riveted to the chamber walls at 21 and provided with a heat-resistant lining 22 of asbestos or other similar material.

Because of the presence of this auxiliary heating unit, it is possible to move the endless band l3, and consequently the material which is to be developed, at speeds lower than 22 inches per minute and in some cases as slowly as 4 inches per minute, without substantial wrinkling or deformation of the light-sensitive material. The exact reasons for this improved operation are not entirely known, but it is my theory that the additional heating unit partially dries and stiffens the printing material as it leaves the perforated section of the .plate and developing chamber, so that the accompanying calendaring or ironing of the material will be effective. This ironing efiect is obtained when the material is moved over the unperforated smooth edge of the developing chamber just prior to the discharge of said material at 23. That point is hereinafter termed the terminal point of pressure.

It will be apparent that the provision of this additional heating unit at the rear edge of the perforated plate greatly increases the range of available operating speeds in developing machines of this type. Since many equivalent forms of construction will be readily apparent to those persons skilled in the art, it is not my intention to limit this invention to the'exact form shown in the drawing. All such equivalent arrangements which fall within the scope of the appended claims should be considered as included in this invention.

Now therefore I claim:

Apparatus for developing exposed, light sensitive materials which includes in combination, a chamber having as one side thereof a convex wall, an endless gas-tight band in pressure contact with the wall and by and between which and the wall exposed material is moved. means for introducing developer within the chamber and for vaporizing it, perforations in that part of the wall over which the material is first moved by the band and a smooth unperforated surface extending from the perforated part of the wall to the edge thereof at which the pressure between the band and wall surface is released, a partition within said chamber so disposed as to insulate a part thereof extending from the perforated section of the wall to a point which includes the terminal point of pressure between the band and wall, and heating means within the insulated section, whereby exposed material will, as it is moved over the chamber wall, first be exposed to the developing vapor and then be calendered as it is passed under pressure between the band and smooth, heated surface of the wall.

HERBERT H. STEGLICH. 

